Population genetics is concerned with the development of theories of natural populations, incorporating basic Mendelian processes, selection, mutation, systems of mating, and the impact of environmental forces. Quantitative genetics studies the nature of the observed variability of natural and man-produced biological populations with regard to measurable attributes. In the last resort, almost every attribute of an individual of a population is quantitative as opposed to qualitative. A more complete theory of genetic populations must take account of this basic fact, and must then become involved in the theory of quantitative genetics. In our view the theory of quantitative genetics is of great importance to a wide variety of human aims and there is a need for a review and evaluation of the status of the theory. We have contacted leading workers of the world in the area and have received strong encouragement to attempt to organize an international conference which we are now attempting to do. A tentative plan is to have a one-week conference with sessions on general theory, relevance and impact of modern molecular biology, applications in plants and animals, applications in humans, statistical aspects of the theories, and finally an overall reveiw. We hope to have presentations by about twenty-five principal speakers with a significant portion of time for discussion and short presentations.